London rolls out the blue carpet for Cameron blockbuster

Some 15 years and a reported £300m after the idea first occurred to him, director James Cameron said that seeing the 3-D world of Avatar on the big screen, at its world premiere in London last night was a "big relief".

"It's a great feeling of satisfaction," said the director, whose last Hollywood movie was the blockbuster Titanic. "It's a big relief for me to be done with the film and to know that people are finally going to be seeing it, that it's out of my hands at this point."

Cameron says he initially conceived the idea for the movie in 1995, and has been waiting for technology to catch up. The story is set in the 22nd century on a distant planet, Pandora, where humans cannot breathe the air, but control hybrid creatures – avatars – via a mental link, and pillage natural resources. The fact that political and environmental reality has caught up, too, will do the film no harm.

Cameron said: "I see it as a broader metaphor, not so intensely politicised as some would make it, but rather that's how we treat the natural world as well.

"There's a sense of entitlement – 'We're here, we're big, we've got the guns, we've got the technology, we've got the brains, we therefore are entitled to every damn' thing on this planet.'

"That's not how it works and we're going to find out the hard way if we don't wise up and start seeking a life that's in balance with the natural cycles of life on earth."

The movie was made using a virtual camera and computer-generated animation. Reports of its cost vary from £150m to £300m, which would make it the most expensive film in history.

The opening 15 minutes were screened around the world earlier this year. Reactions were mixed – some found the CGI sequences, featuring the blue humanoid characters, off-putting. One critic dubbed the film "Dancing With Smurfs".

Cameron joined Avatar's stars – Sigourney Weaver, Sam Worthington, Zoe Saldana and Stephen Lang – on the blue carpet in London's Leicester Square. The film goes on general release a week today.